“After reviewing the document in camera, the court concludes that it largely rehashes information already made public, thus obviating any need for secrecy,” the judge said.

Two groups, Judicial Watch and Cause of Action Institute, have been prodding the government for more information about the Clinton emails, and they cheered the judge’s ruling as a victory for transparency.

“This order makes public details submitted by the government about the FBI’s efforts to recover then-Secretary Clinton’s unlawfully removed emails. Americans deserve to know the full scope of that investigation,” said COA President John J. Vecchione.

Tom Fitton, president of Judicial Watch, said he didn’t understand why the Trump administration was still backing the Obama administration’s fight against transparency in this case.

“President Trump ought to be outraged his appointees are protecting Hillary Clinton,” Mr. Fitton said. “The State Department should initiate action with the Justice Department — and both agencies should finally take the necessary steps to recover all the government emails Hillary Clinton unlawfully removed.”

The case stems from questions about Mrs. Clinton’s secret server and the trove of emails she belatedly turned over.

The former secretary of state said she included all of her work-related emails in what she returned to the department, then wiped the server — which she had kept at her home in New York — clean.

But the FBI managed to obtain some emails that were clearly work-related, but which the former senator and first lady didn’t turn over, raising questions about what else may be out there.

Mrs. Clinton’s critics have said the FBI needs to make a more robust effort to try to recover those messages.

The FBI this week also refused an open-records request from a lawyer seeking the bureau’s file on its investigation into Mrs. Clinton. The FBI said there was too little public interest in the case to outweigh Mrs. Clinton’s privacy interests.